Bi-2-oxazoline and oxazine compounds derived from cyanoethylated poly(ethylene glycols) and poly(propylene glycols)

ABSTRACT

WHERE R, R&#39;&#39;, and R&#39;&#39;&#39;&#39; can be H or alkyl containing from one to four carbon atoms, where X is (C2H4O) or (C2H6O), where n is a value from 1 to 50 inclusive and where m is 2 or 3.   Bi-2-oxazoline and oxazine compositions derived from cyanoethylated poly(ethylene and propylene) glycols and having the formula:

United States Patent Tomalia et al.

[ 1 E Re. 28,669

[ Reissued Dec. 30, 1975 [75] lnventorsz Donald A. Tomalia; David P.Sheetz,

both of Midland, Mich.

[73] Assignee: The Dow ChemicalCompany,

Midland, Mich.

[22] Filed: Aug. 22, 1974 [21] Appl. No.: 499,673

Related U.S. Patent Documents Reissue of:

[64] Patent No.: 3,730,915

Issued: May 1, 1973 Appl. No.: 224,587 Filed: Feb. 8, 1972 US.Applications:

[60] Division of Ser. No. 129,262, March 29, i971, Pat. No. 3,763,177,which is a continuation-in-part of Ser. No. 835,9]0, June 16, 1969,abandoned.

[52] US. Cl. 260/2 N; 260/2 R; 260/2 EP; 260/47 EP; 260/53 EP; 260/47 N;260/246 R; 260/307 F [5 1] Int. Cl. C08G 59/26 [58] Field of Search260/2 N, 47 EN, 53 EP [56] References Cited UNITED STATES PATENTS 2/l972Tomalia 260/240 E 2/1972 Tomalia et al. 260/47 EN PrimaryExaminer-Donald E. Czaja Assistant Examiner-Earl A. Nielsen Attorney,Agent, or FirmRonald G. Brookens [57] ABSTRACT Bi-2-oxazoline andoxazine compositions derived from cyanoethylated poly(ethylene andpropylene) glycols and having the formula:

where R, R, and R can be H or alkyl containing from one to four carbonatoms, where X is (C,H,O) or (C HBO), where n is a value from 1 to 50inclusive and where m is 2 or 3.

1 Claim, No Drawings Bl-Z-OXAZOLINE AND OXAZINE COMPOUNDS DERIVED FROMCYANOETHYLATED POLY(ETHYLENE GLYCOLS) AND POLY(PROPYLENE GLYCOLS) Matterenclosed in heavy brackets I: appears in the original patent but formsno part of this reissue specification; matter printed in italicsindicates the additions made by reissue.

This is a division of application Ser. No. l29,262, filed Mar. 29, I97],now US. Pat. No. 3,763,177, issued Oct. 2, 1973, which is acontinuation-in-part of application Ser. No. 835,9l filed June 19, 1969,and now abandoned.

BACKGROUND OF THE INVENTION This invention is concerned with novelbi-2-oxazoline and oxazine compositions derived from cyanoethylatedpoly(ethylene and propylene) glycols, which compositions when reactedwith polyepoxides or polysulfhydryl compounds form elastomeric polymershaving desirable properties of strength, durability and resistance totearing. Such bi--2-oxazoline and oxazine compositions can also be curedin the presence of boron trifluoride to provide useful, rigid polymericmaterials.

THE .PRIOR ART The polymerization of various monooxazoline compounds isdescribed in US. Pat. No. 3,373,194 and also in the Journal of PolymerScience, Volume 4 (part A-l) (1966), page 2253 and following.

DESCRIPTION OF THE PRESENT INVENTION According to the present inventioncyanoethylated.

polyethylene glycols and prolypropylene glycols are treated withhydrogen chloride and with ethylene chlorohydrin or propylenechlorohydrin to obtain amidate derivatives which are then treated with acyclizing agent such as triethylamine to obtain a polyethylene glycol orpolypropylene glycol doubly terminated with oxazoline or oxazine groupswhich can be substituted; these oxazine or oxazoline terminatedcompounds are difunctional monomers adapted to be cured to obtainelastomeric polymers.

The doubly nitrile terminated, that is to say, the biscyanoalkylpolyglycols utilized can be prepared by combining the polyglycol, in asolvent, such as one which is advantageously at least 30 volume percentliquid paraffinic hydrocarbon, and, in such solvent, combining also anunsaturated nitrile compound such as acrylonitrile, methacrylonitrile,or crotonitrile. The reaction is catalyzed by strong bases, such asalkali metal oxides, hydroxides, alkoxide, hydrides, cyanides, andamides or the alkali metal salts of the polyglycol to be cyanoalkylated;also, the strongly basic quaternary ammonium compounds such astetramethylammonium hydroxide, benzyl trimethyl ammonium hydroxide andthe like.

The so formed bis-cyanoalkyl polyglycols are then maintained attemperatures near to the freezing temperature of water and undernitrogen purge and in liquid phase, and reacted with a loweralkylenechlorohydrin and also with hydrogen chloride gas. Desirably, thereacting cyanoethylated loweralkylene glycol is dissolved in liquidsolvent and the loweralkylene chlo rohydrin, typically, ethylenechlorohydrin, added slowly, portionwise, and with stirring.

After the reactants have been combined, while maintaining nitrogen purgeand temperatures near to the 5 freezing temperature of water, anadditional time of reaction is provided during which the reaction can goforward to completion. Thereafter, a portion of further solvent can beadded and the resulting mixture placed under vacuum to withdraw portionsof unconsumed hydrogen chloride. After an hour or so under partialvacuum, an additional portion of solvent can be added and the resultingmixture warmed to room temperature or somewhat above, such as to 3545and the subatmospheric pressure maintained for an additional period oftime to withdraw further portions of hydrogen chloride.

Following the vaporization and removal of unconsumed hydrogen chloride,the mixture is ready to be cyclized.

In cyclizing the terminal reaction product moieties present, thereaction mixture is cooled to a tempera' ture near to the freezingtemperature of water; and a cyclizing agent, which must be an agent forthe acceptance of the elements of hydrogen chloride, is added slowly,portionwise, and with stirring over a period of time. Advantageously,during this combining process, chilling also is continued.

Upon the completion of the addition of cyclizing agent, the resultingmixture is then heated at a reaction temperature which can be from roomtemperature to approximately 50 for a reaction period of time such asfrom 1 to 8 hours, to carry to completion the cyclizing reaction andthereafter, the resulting mixture cooled to room temperature and pouredinto water. While the phase separation effected by water dispersion isnot perfect or complete, it is a useful and convenient method of workingup the desired product. In general, the hydrochloride of reaction, suchas an amine hydrochloride, is water soluble and is removed and discardedin the water phase; in general, the desired bisoxazine or oxazolineproduct is much less water soluble and is separated and derived from theorganic phase.

Upon separation of the organic from the aqueous phase, the product canthen be distilled, to strip off and remove solvent and volatilesubstances not desired, and, over a modest and distinct temperaturerange, depending upon the distribution of polymeric species of thestarting polyloweralkylene glycol, one obtains, in satisfactorily highpurity, the bisoxazine or oxazoline polyloweralkylene glycol derivativeof the present invention.

Identity of the product is readily checked by infrared spectrum whichmay be scrutinized for the inflection representing the stretching modeof the moietyC=Nlocated at approximately I673 reciprocal centimeters butsubject to modest variation depending upon adjacent groups, as is knownin the infrared art. Also, elemental analysis can be relied upon andshould be accurate to a close approximation: the interpretation ofelemental analysis may be facilitated by comparison with elementalanalysis of the polyloweralkylene glycol starting material.

The resulting materials, under ordinary chemical storage conditions, arestable and can be held in storage until desired.

When it is desired to cure the difunctional polymers according to thepresent invention to obtain elastomeric high-polymer products, thedifunctional monomer of the present invention is mixed and stirred intoa curable polyepoxide and thereafter cured in known manner; or is mixedand combined with a polysulfhydryl compound and the resulting mixturesubjected to known curing catalysis and similar influences; or theresulting polyfunctional monomer is mixed with a monooxazoline oroxazine compound together with catalyst such as for example, borontrifluoride or a complex of boron trifluoride in catalytic amount andthereafter heated to obtain a polymeric material. The homopolymers areprepared under similar catalysis.

The polyepoxide is any curable polyepoxide of the general formula e.g.those haying an average of more than one 1,2- epoxy aliphatic group,average. A representative mate rial is the diglycidyl ether of bisphenolA or bisphenol F; similarly, the condensation products of such glycidylethers with further bisphenol further epoxylated by reaction withfurther portions of epichlorohydrin are usefully employed. Also, thepolyepoxides of polyloweralkylene glycols are usefully employed.Similarly, epoxylated novolak compounds are employed when desired, andalso polyepoxide compounds derived from the epoxylation ofuncharacterized and incompletely identified polyhydroxy-aromatic sideproducts from industrial processes. When it is desired to obtain a curedepoxy resin of low flammability or substantially fireproof, a startingmaterial of choice will comprise, or may entirely consist of a partiallyto completely brominated polyepoxide starting material. While brominatedstarting materials are usually the fire-retardant materials of choice,giving rise to a partially brominated cured epoxy resins, materialsotherwise halogenated are also used when desired.

The polysulfhydryl compound which can be used is any such compoundhaving the general structure HS-SH such as, for example,l,4-dimercaptobenzene or the like.

The following examples illustrate that best methods known of practicingthe present invention.

EXAMPLE 1 Preparation of 2 ,2 '-propylenebis(oxyethylene)bis-2-oxazoline Into a flask was placed 91 grams, 0.5 mole, of 3,3'(-propylenedioxy) dipropionitrile together with 80.5 grams, 1.0 mole,ethylene chlorohydrin, dissolved together in 100 milliliters methylenechloride. Temperature of the solution was lowered to to 5 C.; and atthis temperature, with continued stirring, hydrogen chlrodie gas, 1 l 1grams, was introduced into the stirred reactants and below the surfaceof them through a sparger.

Upon the completion of the addition of hydrogen chloride gas, stirringwas continued and the resulting solution was then purged with nitrogengas which was passed in through a sparger for one hour; and the mixturewas thus thereafter maintained, with continued 4 stirring, at 0 to 5 C.overnight, to carry the reaction to completion.

Thereafter, to remove excess and unreacted hydrogen chloride, theresulting solution was diluted with 200 milliliters dichloromethane, andthe resulting solution placed under vacuum of approximately 20 to 30millimeters mercury absolute for about an hourv At the end of this time,a further 100 milliliter portion of dichloromethane was added whereuponthe entire solution was warmed to approximately 35 C., while beingmaintained under the indicated subatmospheric pressure for approximatelyan additional hour.

Thereafter, the resulting reaction solution was chilled to 0 to 5 C.,and thereinto, dropwise, and with continuous stirring during a period ofabout an hour, triethylamine in the amount of 222 grams, 2.2 gram moles,was introduced. The resulting mixture was then heated at 35-40 for 4hours, cooled to room temperature, and poured into 750 milliliters ofwater.

In general, the desired product segregated as a relatively insolubleorganic layer whereas byproducts of reaction including triethylaminehydrochloride segregated in an aqueous layer. The organic layer wasseparated, and from it solvent was removed, to obtain 107.7 gramspercent by weight of starting dipropionitrile compound) of crudeproduct. Most of the loss is believed to have occurred through partialsolubility of product in water.

The crude product was placed in a high vacuum still, and carefullydistilled to obtain 79 grams (yield of 59 percent by weight of startingdipropionitrile) of a pale yellow liquid boiling at l00-l02 C. under apressure of 1.5 X 10 millimeters mercury, absolute.

Upon completion of the high vacuum distillation, the product wasscrutinized by infrared spectrum, and found to exhibit, among otherexpected features, a sharp absorption maximum at 1673 reciprocalcentimeters, indicative of the 2-oxazoline structure. A sample of theproduct was analyzed for carbon, hydrogen, and nitrogen and found tocontain 57.9, 8.58 and 10.2 weight percent by total weight of sample ofthese elements, as compared with theoretical values of 57.8, 8.!5, and10.3 percent respectively.

A mixture of equimolecular amounts of 2,2'-propylene bis(oxyethylene)bis(2-oxazoline) and 2,2-bis(p- (2,3-epoxypropoxy)phenyl) propane wasintimately mixed and stirred to obtain a substantially colorless,mobile, homogeneous solution of viscosity substantially lower than thatof the starting epoxypropoxyphenyl propane compound.

The resulting solution was divided, again, into samples designated as A,B, and C and each was maintained in a small, open, aluminum tray. SampleA, allowed to stand at room temperature (approximately 25 C.) for 1month showed substantially no change. The sample remained a colorless,mobile liquid of low viscosity. Sample B was heated for 4 hours at 250F. in an open tray whereas Sample C was heated for 10 hours at 350 F.also in an open tray. After such heating, Sample B was somewhatsusceptible of solvent deterioration and was in the form of a Lightyellow, tough resin. After heating, Sample C was a thin plate or chip ofa brown, tough, horny resin upon which prolonged soaking in acetone,water, or benzene had no visible effect.

EXAMPLE 2 Preparation of 2,2'-ethylenebis (oxyethylene) bis-2-oxazolineThe compound prepared according to the instant example is an immediatelower homologue of the compound of Example 1.

A solution was prepared, consisting of 84 grams, 0.5 gram-mole, of3,3'(ethylenedioxy)dipropionitrile and 80.5 grams, 1 gram mole, ofethylene chlorohydrin, both dissolved together in 100 milliliters ofdichloromethane, at -5 C. At this temperature, and with continuousstirring, hydrogen chloride gas (75 grams, total) was introduced by asparger beneath the surface of the pool of flask contents.

Upon completion of the introduction of hydrogen chloride gas, stirringwas continued, and the resulting solution was purged with nitrogenintroduced through a sparger for one hour, and thereafter placed andmaintained at a temperature of 0-5 C. with continued stirring,overnight, to carry the reaction to completion.

The next morning approximately 15 hours after the product was set toundergo prolonged reaction, 200 milliliters dichloromethane was added,and the reaction mixture then placed under subatmo spheric pressure ofapproximately 20-30 millimeters mercury, absolute for an hour to removeexcess hydrogen chloride. Thereafter, 100 milliliters further ofdichloromethane was added, and the resulting solution was warmed at 35C.while under indicated subatmospheric pressure for an hour further.

it has been noted, supra, that the cyclizing agents to be employedaccording to the present invention are acceptors for hydrogen halide. Itfollows that, in any embodiment of this invention, not only the presentexample, that any excess hydrogen chloride, if no vacuum removal isattempted, or remaining after vacuum removal, is promptly accepted andbound in readily removable form by the cyclizing agent. Therefore, theindicated vacuum removal of excess hydrogen chloride, while highlydesirable from the standpoint of economy of cyclizing agent, is notcritical to the practice of the present invention, but is, rather, amatter of convenience and economy.

The reaction mixture, after such vacuum removal of hydrogen chloride inexcess, was then cooled to 0 to 5 C., and 222 grams, 2.2 gram moles,triethylamine was added dropwise, and over a period of one hour. Theresulting mixture was then heated, with continued stirring, at 35-40 C.,for 4 hours, whereupon it was cooled to room temperature and thereafterpoured into 750 milliliters water. In general, the triethylaminehydrochloride of reaction segregated into the water layer, while desiredproduct segregated into a separate organic layer, although the productwas to some slight extent soluble in the aqueous phase and portions werethereby lost. The aqueous layer was separated, and concentrated by vaporremoval of solvent, to obtain 78.2 grams (61 percent) of the crudeproduct as a light yellow liquid. The resulting crude product wasdistilled in a high vacuum still to obtain a major fraction boiling at1l21l4 C. under a pressure of 2.5 X millimeters mercury, absolute, whichliquid promptly solidified upon cooling to obtain an off-white solidmelting at 35-" C The product was scrutinized, and found to manifest aninfrared spectrum with a pronounced inflection at 1675 reciprocalcentimeters, characteristic of the 2- oxazoline nucleus.

A further portion of the redistilled product was analyzed and found tohave contents of carbon, hydrogen, and nitrogen, respectively, of 55.4,8.12, and 10.7 weight percent by weight of total sample of products ascompared with theoretical values of 56.3, 7.80, and 10.9, respectively.

A mixture of equimolecular amounts of 2,2'-ethylene bis(oxyethylene)bis(2-oxazoline) and 2,2 -bis(p- (2,3-epoxypropoxy)phenyl)propane,presently 1.28 gram of the former (0.005 mole) and 1.9 gram of thelatter (also 0.005 mole) were combined to obtain a colorless, mobile,homogeneous, viscous, readily pourable, substantially water clearliquid. The liquid is curable with heat to obtain an epoxy resin.

In the instant example the resulting liquid was divided into threeapproximately equal but unweighed portions, and they were designated asA, B, and C. Portion A was permitted to stand in open air in a smallaluminum tray, and was observed during a month. Portion B was heated for4 hours at 250 F. (approximately 121 C.) and Portion C was heated for 10hours at 350 F. (approximately 177 C.), each in a small, open alu minumtray. Whereas the sample maintained at room temperature underwent novisible change during a month, the heated samples both became hard.Sample B became a very pale yellow, tough resin which was swellable andsusceptible of deterioration in physical form upon being soaked inacetone, water, or benzene. Sample C became brown, tough, and in thethin plate here prepared, was yielding and horny in character. Prolongedsoaking in water and benzene were without effect and prolonged soakingin acetone increased the apparent elasticity of the material slightly.

EXAMPLE 3 Bis2-oxazoline terminated polypropylene glycol, from startingpolyglycol of average molecular weight of 400 The startingbis(2-cyanoethyl)ether according to the instant invention is thebis(2-cyanoethyl)ether derivative of polyglycol P-400. This polyglycolis a polypropylene glycol which, prior to cyanoethylation, has anaverage molecular weight of approximately 400, representingapproximately 6% average recurring propylene glycol units.

Of this bis(2-cyanoethyl)ether of polyglycol P-400, 510 grams (1.0 mole)and also 161 grams, 20 moles, ethylene chlorohydrin, were dissolvedtogether in 200 milliliters dichloromethane. The resulting solution wascooled to a temperature of 05 C. Stirring was begun, and, withcontinuous stirring, hydrogen chloride gas was introduced thereinto andbeneath the surface of the pool of the liquid reaction mixture bysparger until 265 grams had been introduced. The introduction of the gastook approximately four hours.

Following the completion of the introduction of hydrogen chloride, theresulting reaction mixture was 7 maintained at the indicatedtemperature, and stirring was continued overnight.

Thereafter, a portion of the mixture was further treated todehydrohalogenate and cyclize as follows. To the portion employed, 400milliliters dichloromethane was added, after which the resultingsolution was maintained, with stirring, for one hour under pressure ofapproximately 20-30 millimeters mercury, absolute, then heated for 1hour at 35-40 C. under atmospheric pressure, and, while the sametemperature was maintained, the ambient pressure dropped to againapproximately 20-30 millimeters mercury, absolute.

Following this procedure, the resulting mixture was cooled to -l0, and,at that temperature, 370 grams, 3.65 gram moles, triethylamine wasadded, dropwise, over a period of approximately I65 minutes. The mixturewas then heated at 4550 during 4 hours, then cooled to room temperature,and subsequently poured into I50 milliliters water. The water mixturewas stirred, to wash water-soluble components out of the resultingorganic product, the organic product permitted to segregate as aseparate organic layer which was separated and removed, and from itsolvent evaporated to obtain 280 grams of a dark orange syrup. Thissyrup was freed of volatiles in a high vacuum still at I0 millimetersmercury pressure, absolute.

A sample of the high vacuum distilled product was examined by bothnuclear magnetic resonance spectrum and infrared spectrum analysis, andboth spectra were found to be consistent with those expected of thebis-2-oxazoline structure. The structure was further confirmed bypolymerizing the product in the manners indicated, foregoing, andobtaining polymers entirely consistent with this invention.

EXAMPLE 4 Bis 2-oxazoline terminated polypropylene glycol, from startingpolyglycol of average molecular weight of The startingbis(2-cyanoethyl)ether according to the instant invention is thebis(2-cyanoethyl)ether derivative of polyglycol P-I200. This polyglycolis polypropylene glycol which, prior to cyanoethylation, has an averagemolecular weight of approximately I200, rep resenting approximately 20average recurring propyene glycol units.

Of this bis(2-cyanoethyl)ether of polyglycol P-1200, 328 grams, 0.25gram mole, together with 60 grams, 3.75 gram mole, of ethylenechlorohydrin, was dispersed in 125 millimeters dichloromethane. Theresultng solution was cooled to 0-5 C., with stirring, and, it thistemperature, during 3.5 hours, hydrogen chlo 'ide gas was introduced, bysparger, until I55 grams tad been taken up. Introduction of furtherhydrogen :hloride was then terminated, but stirring and cooling werecontinued at the indicated temperature, ovcriight, approximately I5hours. At the conclusion of :his interval, I00 millilitersdichloromethane was added and the resulting mixture placed under apressure of -30 millimeters mercury, absolute, for approxinately an hourto remove excess hydrogen chloride. Thereafter, the mixture was heatedunder atmospheric Jressure at 35 for an hour, and then held at 35 under8 pressure of 2040 millimeters mercury, absolute, for further hour.

Following the completion of these steps for the re moval of excesshydrogen chloride, the reaction mixture was cooled to 05 C., and thecyclizing of the amidate hydrochloride was begun. To cyclize, I l lgrams (1.1 gram moles) of triethylamine was added, dropwise, and withcontinuous stirring, over approxi mately I05 minutes. Following thecompletion of the addition of the triethylamine, 200 milliliters furtherdichloromethane was added, and the mixture heated at 4550 for 4 hours tocarry the reaction to completion. Upon cooling to room temperature, 500milliliters dischloromethane was added, and, in the resultingessentially organic solvent system, byproducts tended to settle asparticulate solids, forming a slurry. The slurry was filtered, and theresidue comprised 208.3 grams triethylamine hydrochloride. From theliquid filtrate, by vaporization and removal of solvent, 24] .5 grams ofa dark orange product oil were obtained. From a 134.8 gram sample ofthis oil, volatiles were removed under a pressure of IO millimetersabsolute mercury pressure. The resulting product, also an oil, wasexamined by nuclear magnetic resonance and infrared spectrum, and thespectra presented, uniformly, the features that were expected of theproposed bis-2-oxazoline polypropylene glycol structure. Further, theproduct was readily curable in a polymerization reaction with anelastomer consistent with the present invention.

EXAMPLE 5 The present example is carried out in all respects as wasExample 3, except that to the bis(2-cyanoethyl)ether of the polyglycolP-400, instead of ethylene chlorohydrin in the amount of two moles,there are added two moles of the mixed isomeric propylene chlorohydrins,namely, l-chloro-Z-propanol and Z-chloro-I- propanol. Except for thesesubstitutions, the substances and relative amounts employed areidentical with those of Example 3.

In the resulting cyclized product, I-chloro-2- propanol gives rise tothe 5-methyl-2-oxazolin-2-yl product whereas the 2-chloro-I -propanolproduct gives rise to a 4-methyl-2-oxazolin-2-yl product.Correspondingly, the product of the present example, following vacuumdistillation is a mixture of the two said isomers. It is, similar tothose foregoing, useful in the preparation of an elastomcric polymer asindicated.

What is claimed is:

l. A latent curable polyepoxide composition comprising in combination, acurable poly-I,2-epoxyalkyl compound having an average of more than one1,2- epoxyaliphatic group per molecule and a curing amount of [abi-2-oxazoline derived from cyanoethylated poly(ethylene and propylene)glycols and 1 a compound having the formula where R, R and R" can be Hor alkyl [containing 1 of from one to four carbon atoms, where X is (Cl-[ 0) or (C H O), where n is I to 50 inclusive and where m is 2 or 3.

1. A LATENT CURABLE POLYEPOXIDE COMPOSITION COMPRISING IN COMBINATION, ACURABLE POLY-1,2-EPOXYALKYL COMPOUND HAVING AN AVERAGE OF MORE THAN ONE1,2-EPOXYALIPHATIC GROUP PER MOLECULE AND A CURING AMOUNT OF (ABI-2-OXAZOLINE DERIVED FROM CYANOETHYLATED POLY(ETHYLENE AND PROPYLENE)GLYCOLS AND) A COMPOUND HAVING THE FORMULA